Typewriting machine



'w. F. HELMOND.

TYFEWRITING MACHINE.

APPLICATION FILEQ-IUNE 19. I919- Patented May 2, 1922.

2 SHEETS-SHEET l- W. F.'HELMOND.

TYPEWRITING MACHINE- APPLICATION 'mzn JUNE 19. 1919.

Patented May 2, 1922.-

'2 SHEETS-SHEET 2 /m e/7f0/': MW 7% y 3 ii current, stares ea'ranr OFFICE.

WILLIAM F. HEL-MOND, or HARTFORD, oonnnoriour, ASSIGN'OR T0 unnnnwoon TYPEWRITER company, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

TYPEWEITING MACHINE.

Specification of Letters Patent.

"Patented May 2,1922

Application filed June 19, 1919. Serial No. 305,255.

To all whom it may concern Be it known that I, WILLIAM F. HEL- MOND, a citizen of the United States, resid-- upon depression of a. back-spacing key against the action of a spring associated therewith, a link connected to theback-spacing dog or pawl at one side of its pivot will be actuated to permit the pawl to be moved into engagement with the usual rack, by means of a spring acting on the pawlcarrier, and upon said carrier reaching its forward limiting pawl-engaging position, the pawl will be swung about its pivot, by the back-spacing key acting through the connecting link, to back-space the rack and consequently the carriage. Upon release of said back-spacing key the spring associated therewith will cause the link to move in a reverse direction and disengage the pawl from the rack, and thereafter move said pawl tonormal position on its carrier and restore the latter to normal position against the action of the spring associated therewith.

Hitherto, the shaft carrying the backspacing key-lever has been supported beneath the usual key-lever bridge at the rear of the machine, and the forward end of the actuating arm for the link connected to the back-spacing pawl has been positioned directly beneath the rack; consequently the leverage exerted by the link to turn thebaclrthe back-spacing pawl is bent so as to extend under the bell-crank bridge and is pivotally connected to the forward end of the arm extending thereunder. This bent link obviously has the same effect as would be obtained by a straight link connecting the pivot point on the forwardly'extending arm and the pivot point for the link on the backspacing pawl, thus giving much greater leverage and enabling the use of a lighter spring associated with the back-spacing keylever than would otherwise be required.

. It will be seen that by the present improved structure, it is made possible to omit the usual pawl latch and the usual spring connecting the pawl and the link, suchv as shown in said patent, and that greater simplicity of structure and ease of action are thereby obtained.

Other features and inafter appear.

. In the accompanying drawings,

advantages will here Figure 1 is a diagrammatic side elevation,

partly in section, illustrating my invention as applied to an Underwood typewriting machine.v V

F i ure 2 is a fragmentary front view, showlng the back-spacing pawl tin-normal position.

Figure 3 is a View similar'to Figure 2, showing the parts in the position assumed at the end of a back-spacing movement.

Figure 4 is a skeleton perspective view of the parts constituting the invention.

Figure 5 is a side View from the right of the parts positioned, as shown in Figure 3.

In the machine herein disclosed, depression of character keys 1 will act through keylevers 2 and bell-cranks 3, to swing type-bars 4 upwardly and rearwardly to cause engage.- ment of types 5 with the platen 6, rotatably supported in the platen frame 7 mounted in a carriage 8, which is carried on front and rear rails 9 and 10, respectively, and isurged in one direction by means ofthe usual strap 11 and spring drum 12. I if The movement of the carriage, under urging of spring drum 12, is controlled by means of a rack 13 connected with the carriage 8 by means of a rod 18, and springs 19 positioned between said bridge 17 and key-levers 2 urge sa1d1 levers to their normal positions.

The machine is also provided with a second bridge 20, in which the bell-cranks 3 are pivoted by'ineans of a rod 21.

Whena back spacing'action is desired, a

back-space key 22 is depressed, and such movement is transmitted by means of a lever .7

23:to a shaft 24 mounted in a bracket 25 on the'front ofbridge 17. Slightly to the right of the center of the machine, an arm 26* is secured to shaft 24, and a head 27 of said arm 26=lies under saidhell-crank bridge 20. A-

restorin-gspring 2 8 connectedto a pin 29, passing-through said head 27 'andto' bracket 25-, tend sto hold the back-space key'in raised position.

Upon'depression of key 22, andconsequent depres'sio'nof arm 26, movement is transmitted' to a bent link 30 secured'to head 27 by means of pin 29 and" 1)ivotecl-' loosely at vided with a hook 36 which engages a stud or pin 37 mounted on a fixed part" of the frame for' the purpose of limiting the move- H nient of said'support. The upper end ofsaid 30'" support is provided with the usual hook to prevent upward displacement of said rack 13 during the back-spacing operation. The

back-space pawl 33 is mounted for letterspacing movement on support 34 by'm'eans of' a pivot 38, whose axis is at'right angles to that at the carrier pivot 35, so as to form therewith a universal ioint mountin for the u v 7 h pawl; 33. The pivot 31, connecting the upper end of the link 30 to the pawl arnr 32, has a sufiiciently loose connection with this pawl-arm tc permit the pawl to swing forward and ba'clrward with the pawl-carrier 34L as the latter swings on its pivot The retractive movement of pawl 33 about its pivot 38 on the carrier 34 is limited by a lii'g 39 on the carrler, and said pawl is normally held in this position by means of spring 28, which normally exerts an-upwaid pressure on link 30 suflicient to hold pawlor dog 33 inret'racted position in engagement with lug 39, and also to hold carrier3lin its rearward pawbdisengaging position against the action of a spring 40 rigidly secured at its lower end to carrier 34%. by means of a pin 41 and engaging stud 37 at its upperend.

It will be seen that downward movement of link 30 has, as its first effect, to relieve the spring' lO from the overpowering opposing influence of the stronger pawl-restoring spring 28, and thereby will enable spring it) to swing carrier 34Cto a pawl engagingposition limited either by engagement of the same With'rack'lS, or by engagement of hook 36 withstud 37, and that as soon asjpawl 33 is brought into engagement'with rack 13 further movement of link 30 will cause dog 33 to be swung to therightto give a back- Spacing movement telmiek 13 i and; Ciiris'- quently toca'rriage 8L It; will beunderstood that the springs 28 and 4-0 exert opposing pressures at the pivot 31, the spring 28 urging the link 30 and pivot-pin 31 in an upward and rearward'direction, whilev the spring 40, acting through the pawl-carrier and the pawl 33 carried thereby, urges the pawl-arm 32 inthe oppo site direction, that is, downward and forward. When the link 30 and-pivot-pin 31 carried thereby are moved dow'nward fland forward as a result of depressing-the space"- key 22, the pawl-carrier 34" and the paw'l 33 carried'thereby are moved forward bythe spring 40, with the result that the pawl-arm 32'will be moved downwardandforward as fast as it is permitted tomove'by' the re treating or downwardly and forwardly mov 30; In view of the fact that the link 30 does not exert any pulling effect upon the pawl-arm 32, it will beevident that tl-iepa'wl" 38 cannot be swung on its pivot 38 until after the forward movement of the pawlcarrier 34; by "the spring 40 has been stopped by the stud 37 or by the rack 13, as'shown' in Figure During this pawl-engaging movement, the spring 40 willholdthepawl 33 tightly against its'b'ack-s'top lug 39, by reason of the fact that tlie'spring {i0 has a tendency to move the pawl-carrier 3e faster than it is permitted to-move by the key-controlled combined downward and forward movement of the link 30, so tliatthereby'up ward and rearward pawl-restraining"pressure is maintained by the pivot 31 on the pawl-arm 32 throughout the pawl-engaging movement of" the carrier 34; and pawl 33.

In the construction heretofore employed, and disclosed in my above-mentioned patent, it was found-necessary to provide a spring pressed latch to prevent the pawl'f from swlnging on its pivot onthe pawl-carrier before this pawl had moved nto engager'nent with the rack, and, furthermore, to provide a spring to reslst the tendency of the oper atlng link to swing the pawl or dog about its pivot, such springco-operating with the latch; In the present invention, the pro vision of the single spring 10 enables the previously-employed latch, the latch spring and the pawl spring all to bedispensed with; It has been found in practice that the present construction operates more easily, freely, smoothly and with more certaintythan in the previous device," so that the eflieienc of the back-spacingmechanism is increased to a marked degree by means of a simple and inexpensive construction. This previous construction, besides being less reliable and less effective than the device provided by the present invention, resulted in a heavy keyaction, whereas in the device of the present invention the key-action has proved much lighter.

The back-spacing movement of rack 13 effects rotation of pinion 14 with reference to escapement wheel 15, which is prevented from moving with the pinion by means of a pivoted dog 42 swung into position to prevent backward rotation of the escapement wheel.' The connection between the dog 4:2 and carrier 34: may be effectedby any suitable means, such, for example, as that shown in said Patent No. 930,962. As is made clear in said patent, unless provision is made of means such as the dog 42, a backspacing movement of rack 13 with pinion 14 would cause a corresponding movement of escapement wheel 15 and of the usual loose dog, and upon release of the backspacing key the escapement wheel, under control of the spring drum, would merely move the loose dog to its original position and no back-spacing would be effected.

Movement of the back-spacing pawl 33 to the right, in the back-spacing operation, is limited by means of a stop 43 at its lower end coming into contact with the pawl-carrier 34, and, due to the manner in which pawl 33 is brought into engagement with rack 13, the limitation of movement of the pawl will also serve to limit the back-spacing movement of the rack.

Upon release of key 22 by the operator at the end of a back-spacing movement, the spring 28 will act to restore key 22 to normal position and will swing the carrier 34 to the rear against the action of the spring 40, to disengage pawl 33 from rack 13, and subsequently the spring 28 will restore said pawl to its normal retracted position on car- Ider 3d. 7

Hitherto, due to position of bridges 17 and 20, it has been thought necessary to use a substantially straight link, extending from the back-space pawl vertically downwardly between the bridges, and to actuate the link by means of an arm on a shaft supported beneath the rear portion of the key-leverlu'idge, said shaft also carrying the back space-key lever. With this construction, the effective action of the link was along a .line passing so close to the pivot or fulcrum of the pawl-carrier that the leverage for turning the carrier about the pivot was very slight, and it was, therefore, necessary to provide a strong resistance to the swinging movement of the pawl relative to said carrier. such, for example, as the spring-pressed latch for the pawl and the pawl-retarding spring, disclosed in my previous patent,

as hereinbefore noted.

hereinbefore referred to, to prevent such movement before the pawl was brought into engagement with the rack. A heavy key action resulted from this arrangement, and in the present case there is provided ,a greater leverage about pivot 35 in order to avoid the use of a very strong spring 28 to overcome spring 40. This long leverage ap plied to the pawl-carrier 3 1 to swing it about the pivot 35 is shown as somewhat greater than the leverage on the pawl 33 to swing it on its pivot 38, and this helps to make sure that the pawl 33 will not be moved on its pivot 38 before it is brought into engagement with the rack 13.

The above-mentioned difficulty has, however, been obviated by supporting shaft 24 at the front of key-lever-bridge 17, with arm 26 extending beneath bridge 20, and by forming link 30 with a bend near its lower end, so that it extends beneath bridge 20 and between the bridges 17 and 20. Obviously said link 30 produces the same effect as would be obtained by a straight link joining pivot pin 29 and pivot 31. The present structure therefore affords a much greater leverage about pivot 35 than was obtained in the structure formerly in use, and makes it possible to use a much weaker spring 28 than would otherwise be required.

It will be obvious that since spring 28 and spring 1-0 oppose each other, they may be selected so as to obtain a very easy key action, and that considerable simplification of the parts for controlling the back-spacing-pawl and the carrier therefor has been effected, Thus it will be seen that the link 30 and the spring 4L0 co-operate with each other and with other parts of the device, not only to give a light key-action, but also to assure that the carrier 34, impelled by the spring 40, will swing the-pawl 33 into engagement with the rack 13 before the pawl is moved on the carrier for effecting the back-spacing operation. Because of the fact that the pawl-carrier 34 is pushed to its pawl-engaging position by the spring 40, instead of being pulled over bythe link 30, as heretofore, friction of the pawl-carrier on its pivot 35, as well as in" all the connections, is lessened, which also, of course, gives an easier key-action.

Variations may be resorted to within. the scope of the invention, and portions of the improvements may be used without others.

Having thus described my invention, I claim:

1. In a typewriting machine, the combination with a traveling carriage and an escapement mechanism therefor including a rack connected to the carriage to travel therewith, of a pawl-carrier mounted for movement transversely to the letter-spacing movement of the rack, a back-spacing pawl mounted on the pawl-carrier to have letters spacing movement thereon, means for limiting the letter-spacing movement of the pawl on the pawl-carrier, a pawl-carrierengaging spring for continually urging the pawl-carrier tmvards the rack for moving the pawl carried thereby into engagement with the rack, and manually-controlled operating means for normally holding the pawl-carrier away from the rack with the pawl disengaged therefrom against the tension of the pawl-engaging spring, but said operating means being operable to permit the pawlengaging spring to move the pawl-carrier towards the rack to engage the pawl therewith, and then said operating means by continued movement acting to move the pawl on the pawl-carrier to move the rack to backspace the carriage.

'2. In a typewriting machine, the combination with a carriage and an escapement mechanism therefor including a rack connected to the carriage to travel therewith, of back-spacing mechanism comprising a pawl-carrier pivoted for pawl-engaging and disengaging movements transversely to the rack, means to limit the movements of the pawl-carrier, a back-spacing pawl pivotedon the pawl-carrier to have letter-spacing movement thereon, means to limit the letterspacing movement of the pawl on the pawlcarrier, a pawl-carrier-engaging spring for continually urging the pawl-carrier toward its position torengaging the pawl with the rack, spring-operated mechanism connected with the pawl to hold the pawl at its retracted letter-spacing position and to hold the pawl-carrier at its pawl-disengaging position against the tension of the pawl-enspring, andmanually-controlled op erating means to overcome the spring-operated mechanism to enable the pawl-engaging spring to move the pawl-carrier to engage the pawl with the rack, and then said operating means by continued movement acting to swing the pawl on the pawl-carrier to move the rack for back-spacing the carriage.

3. In a typewriting machine having keylevers, a bridge in which said levers are pivoted at the rear of the machine, a second bridge in advance of said key-lever bridge and overlying said key-levers, the combination with a traveling carriage and a rack connected therewith in position above the space betweensaid bridges, of a back-space pawl, a support for said pawl pivoted below said :rack for movement to carry said pawl into and out of engagement therewith, and means to swing said support to bring said pawl in engagement with said rack and actuatesaid pawl including a pivotally mounted arm extending under said second bridge, and a dink pivoted at one end to said pawl at a point to one side of the pawl pivot and at the other end to said-arm at a point beneath :said vsecond bridge.

4;. In a typewriting machine, the combination with a traveling carriage and an escapement mechanism therefor including a rack connected to the carriage to travel therewith, of a back-spacing pawl mounted for movement transversely of the rack into and out of engagement therewith and for letter-spacing movement to move the rack tor bac lli-spacing the carriage, a spring for continually urging the pawl in a direction transversely-off "the rack for engaging it therewith, pawl-restoring means including a spring for holding the pawl at its retracted letter-spacing "position and for overcoming the pawl-engaging spring to hold the pawl at its disengaged position clear of the rack, and maniiajll y controlled operating means to overcome the pawl-restoring means to enable the pawl-engaging spring to move the pawl into engagement with the rack, and then said operating means by continued movement acting to impart "letter-spacing movement to the pawl to move the rackfor back-spacing the carriage.

5. In a t-ypewriting machine, the combination with a traveling carriage and an escapement mechanism therefor, including a rack connected to the carriage to travel therewith, oi? back-spacing mechanism comprising'a back-spacing pawl pivoted for universal movement so as to be movable transversely of the rack into and out of engagement therewith, and also so as to have letter-spacing movement in the direction of the length of the rack, key-operated means "for operating the pawl including an operating link connected to the pawl in such manner that its leverage in relation to the pawl as the pawl moves transversely of the rack will be at least as great as the leverage exerted thereby on the pawl for moving it in the direction of the length of the rack, and a restoring spring for the pawl acting through the link for normally holding the pawl out oiengagement with the rack and at a retracted letter-spacing position.

"6. In a typewritingmachine,=the combination with a traveling carriage and an escapement mechanism therefor, including a rack connected to the carriage to travel therewith, of back-spacing mechanism comprising a back-spacing pawl pivoted for movement transversely of the rack into and out et engagement therewith, and also so as to have letter-spacing movement in the direction of the length of the rack, key-operated means for operating the pawl including an operating link connected to the pawl in such manner that its leverage in relation to the pawl as the pawl moves transversely of the rack will be at least as great as the leverage exerted thereby on the pawl for moving it in the direction of the length of the rack, a restoring spring for the pawl acting through the link for normally illOlding the pawl out of engagement with the rack and at a retracted letter-spacing position, and a spring normally overcome by the pawl-restoring spring but continually urging the pawl toward the engaging position for moving it into engagement with the rack when the pawl-rest0ring spring is overcome by the operation of the key.

7. In a typewriting machine, the combination with a travelingcarriage having an escapement rack connected to the carriage to travel therewith, of backspacing mechanism comprising a back-spacing pawl pivoted for movement transversely of the rack into and out of engagement therewith, and also for letter-spacing movement in the direction of the length of the rack, a key-operated lever arm for operating the pawl, an operating link connecting the lever arm with the pawl, a pawl-restoring spring acting through the link for normally holding the pawl out of engagement with the rack and at a retracted letter-spacing position, and a spring normally overcome by the pawl-restoring spring but continually urging the pawl toward the engaging position for moving it transversely of the rack into engagement with the rack when the pawl-restoring spring is overcome by the operation of the key, the key then acting through the lever arm and link to impart letter-spacing movement to the pawl to move the rack for back-spacin the carriage.

WILLIAM F. ELMOND. Witnesses:

WILLIAM P. SMITH, SHIRLEY E. GLEDHILL. 

